EL displays are frequently used to display images such as graphics, text and other types of visual information under ambient light conditions which can vary greatly. In high intensity ambient light conditions, it may become difficult to properly view the images displayed on the EL display. As well, under low ambient light conditions, the images displayed on the EL display may be overly bright.
Accordingly, it is helpful if the EL display is controlled by a dimmer so that image brightness may be increased when the intensity of the ambient light is high. When the intensity of ambient light is low, the brightness of the image may be decreased. The intensity of the display is a function of the maximum voltage applied and in the art the voltage is controlled by a silicon controlled rectifier (SCR). Control of SCR is difficult and has a significant power consumption. Moreover, with portable devices the battery voltage used as a power source will also vary over time and accordingly the intensity of the display tends to fluctuate with the battery voltage.
Accordingly, it is an object of the present application to obviate or mitigate the above disadvantages.